Tuesday, April 19, 2005

Energy Efficiency: LED Lights to Replace Lightbulbs?

Alternative Energy Blog reader Jeff Vail emailed me about this Associated Press article on the increasing use of and advances in LED technology.

LED lamps were unthinkable until the technology cleared a major hurdle just a dozen years ago. Since then, LEDs have evolved quickly and are being adapted for many uses, including pool illumination and reading lights, as evidenced at the Lightfair trade show in New York this week.

More widespread use could lead to big energy savings and a minor revolution in the way we think about lighting.

LEDs have been around since the 60s, but have mostly been relegated to showing the time in an alarm clock or the battery level of a video camera.

They haven't been used as sources of illumination because they, for a long time, could not produce white light - only red, green and yellow. Nichia Chemical of Japan changed that in 1993 when it started producing blue LEDs, which combined with red and green produce white light, opening up a whole new field for the technology.

White LEDs

And the industry has been quick to exploit it. LEDs are based on semiconductor technology, just like computer processors, and are increasing in brightness, energy efficiency and longevity in a way that's reminiscent of the way each year's new crop of processors is faster and cheaper than last year's.

Researchers at the Lighting Research Center at Rensselaer Polytechnic Institute in Troy, N.Y., said they had boosted the light output per watt of a white LED to almost six times that of an incandescent light bulb, beating even a compact fluorescent bulb in efficiency.

The current generation of mass-produced white LEDs is not as effective. It's about twice as good as a light bulb of the same wattage, but the energy savings aren't enough to overcome the major drawback of being expensive.

"It's hard to convince consumers based on energy savings alone," said Nadarajah Narendran, director of lighting research at Rensselaer. "If you look at compact fluorescent lamps, they're four times as efficient as incandescent lights, and how many homes have those? It's less than 5 percent penetration."

But development is brisk, and the Department of Energy has estimated that LED lighting could cut national energy consumption for lighting by 29 percent by 2025. The total savings on U.S. household electric bills until then would be $125 billion.

LEDs have other advantages that are propelling them into niche uses, despite their upfront cost.

LED Traffic Lights

Current white LEDs will last up to 50,000 hours, about 50 times as long as a 60-watt bulb. That's almost six years if they're on constantly.

That makes them attractive for places where changing bulbs is difficult or expensive - like on the outside of buildings or in swimming pools. Osram Sylvania, the lighting subsidiary of German manufacturer Siemens AG (SI), makes 27-foot long strips of flexible, adhesive tape covered in LEDs for such applications. They are also being used in traffic lights and increasingly in car tail lights.

Hotels are interested in using LEDs in bedside lamps to save them the trouble of replacing burned-out bulbs, said Jim Anderson of Lamina Ceramics, which showed off a 6-watt array of LEDs that produce light equivalent to a 20-watt halogen bulb.

LEDs are also durable. Being solid-state, they can resist the vibrations in aircraft and cars, according to Narendran, who has worked with Boeing on designs for aircraft cabins.

BMW LED Tail Light

The feature of LEDs likely to propel them into homes is aesthetic, not practical. Arrays that mix red, green and blue LEDs can produce any color of the rainbow. Instead of a dimmer, you might have three sliding knobs that let you mix color.

"On a very hot day you might want blue light to cool it down a bit, or on a winter day you may want to simulate sunlight," said Steve Landau of Lumileds Lighting, an LED-making joint venture of Agilent Technologies Inc. (A) and Philips Lighting.

Qantas Airways Ltd., the Australian airline, recently outfitted its first-class cabin with LED lighting that shines a deep blue when it's time to sleep.

A system like that would be too expensive for most homes, but industry experts believe the price will come down in a few years as the technology develops.

"We are still in a very young research environment," said Norbert Hiller, vice president at Cree Inc. (CREE) of Durham, N.C., which produces blue and green LEDs. "Our researchers keep surprising us."

23 Comments:

I can't wait for LEDs' price to go down. There are huge efficiency benefits to be had, an I'm sure that in many countries (maybe not the US) it will be possible to convince governments to push these energy efficient measures in the face of the coming energy crisis.

Already here in Quebec the state controlled Hydro-Quebec has been giving away compact fluo bulbs as part of a conservation campaign.

What would be needed would be to either tax incandescent bulbs, or subsidize fluo and LEDs to the point of parity. Then they would take off (and it's not really cheating since it's just internalizing the price of the huge waste of energy of incandescent).

I'm not much on adding taxes here and there; LEDs may be more efficient once operating, but how much of their creation cost is about the energy cost? Fluorescent lamps seem to be the good short-range energy saver; if the LED boys can get their prices down, it might make more sense, but as with photovoltaic cells, the prices is in large part about creation energy.

More than about the cost of creation energy, the question is about creation energy itself.

I have been unable to convince myself that, in the aggregate, my LED lamps and their creation, everything included, result in less energy consumption than conventional lighting.

I'm one of those who thinks it's the availability of concentrated fossil energy reservoirs that has legitimized money proxies in energy analyses [creation energy cost vs. creation energy]. Now that oil depletion is upon us, along with increased competition for what's left and little room in the atmosphere for carbon from other sources, more attention will have to be paid to the energy embedded in products, as opposed to the cost of that energy.

Unless new technologies are more energy efficient [not energy cost efficient] they're not suitable to light the path to the future.

That I see little emphasis on the energy, and continuing emphasis on the cost of the energy, bothers me.

I seriously doubt that an incandescent lightbulb being on for the duration of it's life (a year?) takes less energy than the difference between making a LED or any other kind of more efficient lighting device.

364x24x100W/h=873,600W/h

I seriously doubt that it takes around (873,600W/h - (364*24*22W/h=192192W/h) = 681,408W/h) 681,400 Watt/hour more to produce a compact fluo than an incandescent bulb. That's the amount of electricity that you save if you use a compact fluo of 22 watts (as bright as a 100w incandescent) for a year (and a compact fluo has a lifetime 5x longer than incandescent).

Unless you can prove that it takes 680 kilowatts more to produce a compact fluo than an incandescent, I'll stick to energy efficient lighting.

Money is used as a proxy for energy because it greatly simplifies the analysis. Not much harm is done by using money proxies for energy so long as the energy in question is plentiful and cheap.

We're entering a period, though, in which scarcity due to increasing competition for peaking production, atmospheric degradation and climate change mean that analysis has to change.

That's because, when energy is cheap, energy per dollar is large and the analysis is relatively insensitive to changes in that quantity. When energy per dollar goes down, though, the sensitivity of the analysis to changes in that parameter increases. It's a lot easier to get an incorrect answer. When an analysis is sensitive to changes in a given parameter you'd better get that parameter right, which means the money proxy for energy is less and less legitimate.

If we don't watch out, we'll wind up making long-term decisions tantamount to ordering batteries charged with today's cheap energy rather than building energy sources. If we're not careful, we'll get economically attractive devices that embed more energy than they save.

Your conclusion about incandescent vs. compact fluorescent bulbs may be correct. LED lamps may wind up saving energy. But when I see three times more high-load-factor cooling capacity in a semiconductor fab than in a desert football stadium, I wonder. And that fab is only the tip of the iceberg, under which lie mining, transportation, refining, and a lot more things we don't, or don't want to, think about.

I'm only saying that we'd better start fully understanding what we're doing in terms of energy in and energy out. Energy is not money, and it's not like money.

I'm with you on the personal choice of compact fluorescent over incandescent, but the proof that should be required from a public policy perspective is that new technologies are truly more energy efficient, all things considered, than what they are intended to replace.

Oh, I completely agree that we need completely life-cycle analysis of products to make a good choices, it's something that is badly needed in our society. It would be fairly simple to have eco-labels with that kind of information (I think they are halfway there in Germany).

I just think that it's very doubtful that by the time something like a LED bulb comes to be mass-marketed (in a handful of years, I suppose) the production won't be fairly efficient. Young technologies always have an awkward phase, but after a while it usually gets better if only because being efficient helps make a profit.

WHY do people use nonsense terms like "watts per hour"? Watts are units of power. A horsepower is 746 watts. Would you say "horsepower per hour"?

You say horsepower-hours (horsepower times hours).

You say watt-hours (watts times hours).

Power is energy over time (a rate). Power times time is energy (a quantity). Watt-hours are slightly confused (a rate multiplied by a time), but "watt-hour" is easier to say than "3600 Joules" (a watt is one Joule per second). If you are going to talk about energy, you should learn enough basic physics so that what you say makes sense.

<goes off to walk the peeve so it doesn't make a mess in the house overnight>

With respect to total life-cycle energy used, I believe these things ARE reflected in the cost of the item as well as the cost of operating it. So if we look at the cost of an item PLUS the costs of operating it over it's lifetime, divided by that timeframe so that we get a total cost per time unit of operation, the lowest figure will approximate the most energy effeciency. This is because energy costs make up a large percentage of the total costs, and even when you look at the costs of the materials, you are seeing largely the energy costs required to extract / refine / transport them, and what is left is labor, and a large fraction of that cost comes down to the energy required for sustanance of the laborer. So I believe that cost of the item plus cost of operating it, divided by its lifetime, will yield a figure which very closely follows total life-cycle energy utilization per unit of time.

My school's website, University of Missouri, Columbia. . . actually posted on their website how changing the lighbulbs to flurecent saved them a lot of money, considering some of the schools buildings are rather old. Energy efficieny is one prong of the attack though for the world. I do have concerns that either more energy is needed to make these light bulbs, or that people tend to leave the light on all day instead of turning it off because they think it doesnt cost as much. Conservation must be stressed along with energy efficiency. Also, chemicals are used in making many of these bulbs, and industry must comply with regulations already in place to ensure a clean environment, and if more regulation is needed, and it ends up costing more per bulb, so be it. A basic right in most, if not all, is not free, or cheap energy. The full costs most be taken into consideration. Most governments give subsidies to industry, manipulating any notion of a "free market". Right now in USA, Missouri.. gas is going at $1.99 a gallon and people actually believe that is too high, George Bush is trying to give more money to energy/oil companies in the form of an Energy Bill, on top of the tax breaks already given to them. All this while oil/energy companies are making record profits.

Does anyone know what the energy costs are to produce these?I know that there are Chinese and American "bulbs", but does that go for the individual LEDs as well?What are the chemicals that go into making an LED? Are those toxic, and what about the byproducts? What about compared to an incandecent?

I worked at a semiconductor research lab for a while in college. I personally handled the raw materials that went into the production of an led. Can't recall all of the gasses used but Arsine is one of them. Very pure gasses and metallorganics are used in the process. The more pure, the quicker they go to work - on leds and your body. Sorry that I can't elaborate more on this. The point is they are very nasty substances that require a large amount of resources to produce and handle safely. I was compelled to input because this blog really shed light -hah hah - on energy reduction vs. hazardous production byproducts.

I'm glad to find this blog as it is very fitting with my research. Mymost recent project for a client is one to enhance their profit, getinto their revenue stream by saving on electric utility bills whilereducing maintenance costs. But it seems they have not promoted on theglobal impact of saving the fuel to produce that electricity, nor onthe side effects of the emissions.

Maybe because the product needs no government subsidy to promote itssales?? This was developed purely for the bottom line, and theadvertising agency is just getting started to develop associatedmaterial.

As a lighting designer, I've been able to squeeze every footcandlefrom Light Emitting Diodes (not to be confused here with LED trafficsignals) this is a parking garage luminaire. LEDs are actually lower efficacy than many sources, but control of their light is sometimes more efficient than bulbs, as demonstrated with this product.

This light complies with NPA (National Parking Association) and the IESNAguidelines for parking garage lighting while using only half theenergy and lasts twice as long as conventional lighting. Not tomention it uses no heavy metals or gas, it needs no specialmanufacturing, and it requires no special landfill for disposal (itcan actually be repaired, bulbs cannot).

I understand that some govt. agencies or utilities may offer creditsof sorts for store owners or landlords that do their part for theenvironment, but when the landlord doesn't report such because heneeds no red tape, or because the subsidy is pennies compared to hissavings otherwise, then less is being done to conserve energy.

I am hopeful for comments here, not looking for any commercial leads,but won't turn them away either.Best regards,Pat

I can't see LEDs jumping into energy sensitive illumination applications for still quite a while. My conclusion is based upon LEDs today giving us a CONFIRMED 25 lumens per watt max at real operating temperatures, despite Luxeon's claim they would have 50 lumens per watt this year. Yes, they do claim 50-lumens at 25C junction temperature, but that is not even possible, so the efficacy claims are based on laboratory-perfect conditions, not real world data.

There are some claims out there really far fetched. Check this blogMillennia Technologies where they claim running on AC and 2,200 lumens from 60 watts. Their specs claim 1-watt white LEDs and their photo shows only 40 of those in the luminaire, so that may be 2,200 lumens from 40-watts of LEDs (55 lumens per watt).

The primary benefit of LED technology is the tremendous cost savings for the user as a result of eliminating replacement cost, lowering power consumption, and reducing operating temperatures. Moreover, LED lamps improve efficiency by providing reliable status indication.

I think it's exciting to see these new technologies being developed to replace older out-dated items. LEDs are much more efficient to run and no doubt in the near future will be as cheap (or almost) to produce as current incandecents bulbs are. This spells good news for the consumer and the planet if over all energy consumption can be driven down while all the time maintaining the electical and lighting devices we require. Cheaper lighting (electric bills) and less energy being used, that's win win in my books.

The price of LED light bulbs is comming down, you can find sereral at www.shop.donsgreenstore.com for under $15. The main problem for LEDs I think is that they are still dim bulbs, only good in a couple places in most houses. Thru the Solid State Lighting Iniative and Industry R & D I am confidant light output will increase and price will decrease, but it will take time. Until then CFLs are still our best bet to replace the incandescent bulb.

Thank you for your post, and I think that the LED Lighting Industry Revolution is Mayor, not minor:+ Mr Nakamura received the award for most revolutionary invention of the XX century.+ The state of California already signed a law that makes ilegal the sale of incandescent light bulbs on Jan 1 2011.+ The LED lighting market is expected to grow a 38% every year from 2007 to 2011 reaching 9 Billion USD that year.+LEDs are the true ecological answer to the global warming problem that we are facing currently.

This is a lot like the Ethanol debate. There are very different benefits to each light or transportation energy source, but no one can say for sure which is more environmentally correct.

LEDs and fluorescents only become a good environmental choice when you factor in how much longer they last than incandescents.

Now, LED technology is *galloping* along. (I have a friend in the industry who repeats "LEDs" like the man in The Graduate repeated "plastics.") But for now, my choice is fluorescents - replacement cost and energy/light output is much better. They produce better light, and cost less both to purchase and to operate than LEDs. By the time my compact fluorescent light bulbs burn out, I bet LEDs will be almost even. After two changes of my current bulbs, I bet the choice will be a no-brainer.

Now, for the light fixture three stories up that illuminates my stairwell... my landlord would do well to switch to LEDs...